Resolving intergenotypicStrigaresistance in sorghum

Abstract

AbstractGenetic underpinnings of host-pathogen interactions in the parasitic plantStriga hermonthica,a root parasitic plant that ravages cereals in sub-Saharan Africa, are unclear. We performed a comparative transcriptome study on five genotypes of sorghum exhibiting diverse resistance responses toS. hermonthicausing weighted gene co-expression network analysis (WGCNA). We found thatS. hermonthicaelicits both basal and effector-triggered immunity – like a bona fide pathogen. Resistance response was genotype-specific. Some resistance responses followed the salicylic acid-dependent signaling pathway for systemic acquired resistance characterized by cell wall reinforcements, lignification and callose deposition while in others the WRKY-dependent signaling pathway was activated leading to a hypersensitive response (HR). In some genotypes, both modes of resistance were activated while in others, either mode dominated the resistance response. Cell-wall-based resistance was common to all sorghum genotypes but strongest in IS2814, while HR-based response was specific to N13, IS9830 and IS41724. WGCNA further allowed for pinpointing ofS. hermonthicaresistance causative genes in sorghum. Some highlights include a Glucan synthase-like 10, a pathogenesis-related thaumatin-like family, and a phosphoinositide phosphatase gene. Such candidate genes will form a good basis for subsequent functional validation and possibly future resistance breeding.HighlightParasitic plants of theStrigagenus are major pests to cereals in Africa. We pinpointed genetic causes ofStrigaresistance in sorghum that can be harnessed for future resistance breeding.